Manufacture and treatment of printing plates



Nov. 16 1926. 1,607,189

S. E. DITTMAN muwnc'ruas m TREATMENT or PRINTING rwrss Filed Dec, 21, 1922 3 Sheots -Shent 1 J w/kw:- Samue/ EDilzmn Nov. 16 1926; 1,607,189

3 5. E. DITTMAN I ANUFAGTURB AND TREATMENT OF PRINTING PLATES Filed D c, 21. 1922 3 Sheets-Sheet :5

Patented Nov. 1925.

SAMUEL E. nirrruan, or CHICAGQlLLINOIS, assieno'n ronnr'rnnrnnss newnes conronarron, or cnroaeo, rumors, a oonronnrronjor rumors.

MANUFACTURE AND TREATMENT OF PRINTING PLATES. 1

Application filed December 21, .1922. Serial m. 608,373..

My invention relates to the manufacture of printing plates and the treatmentthereof prior to the mounting of. the plates in the printing press with a view towardreducing or eliminating the make-ready on the printing press, and has particular relation to the leveling of the plates although not limited to this use alone. I

One feature of the invention resides in a simple and effective process for treating printing plates which does not require. a great amount of timeor skill in the practice thereof. I 7

In describing the invention in detail ref eren'ce'is had to the accompanying drawings, forming a part of 7 this specification, and wherein like characters of reference. are used to designate corresponding parts throughout the several'views, and in which Figure 1 is a partially sectional side elevation of a machine for treatingpl'ates by-my process.

Figure 2 is asectional. view of the same taken atright angles to Fig. 1;

Figure 3 is an enlarged p'artial face View ofa printing plate. I a U Figure 4 is an exaggerated partial-section of the same on the'lin'e 4-4 of Fig.3, with a treating sheet applied on the backthereof.

Figure 5 is a similar section of theplate,

with the treating sheet applied on the back thereof, after the plate has been treated."

Figure 6 is an enlarged partial face view of a treating sheet. f j Figures 7 and 8 are partial sections of the treating sheet taken respectively on lines 77 and 8-8 of Fig. .6. i

A suitable press for the practiceof my invention is illustrated in Figs. 1 and Qand includes a frame 1 including abase 2, which constitutes a lower pressure member arranged to coact with an upper pressuremember 3, slidably mounted in: the frame, and actuated for vertical movementhy a screw 4,

threaded inia yoke of the frame and pro-' vided with an operating hand wheel 15. .At its lower end the screw is formed with an ordinary swivel" 6,- arranged tov turn within a cap 7, fixed totheuppe'r pressure member.

' The machine is constructed ofmetal throughout, the opposing faces 8 of the pressure members b'eing flat; and unyielding, and bearers 9 are formed at two opposite ends. of the upper pressure member and depend be low. the surface 8 :0 f the upperpressure mem ber to engage the surface 8 of the lower pressure member 2 to space the surfaces 8 under pressure. In the preferred practice of my invention heat is employed as hereinafter described, and accordingly the pressure members 2 and ;3 are provided with heatlng chambers 11, in which are disposed gas burn- V ers 12 which are connected with gas pipes 13' and 14:, leading froma convenient source of gas supply, the pipe 13 being flexible to accommodate. the vertical movement of the pressuremember 3. Y I

The treatment sheet, of my invention, generally' indicated at '15, includes a fiat sheet of paper or other suitableimaterial 16 to which is secured apattern of materiall? of uniform thickness, normally. hard and un- I yielding but adapted to be rendered plastic for displacement, the pattern providing uniform displacement throughout the material,

and a second-sheet of paper, or other s'uitablematerial, l8 conformed with the pattern of the material and secured'to the opposite face thereof. SeeFigs. 6,7, a-ndz8. The tworsheetsof paper constitute support or backing sheets for the pattern of material and protect it, and where as shown the two sheets conform with opposite faces of the pattern of material a strong-structure is provided which is well adapted to withstand 7 shipment andfstorage.

. The treatment sheet of myinvention 'which of this character which functions very well' contains equal parts of magnesia in pulverlzed form, wheat flour,and powdered graphite, and a s'uitablequantityof japan.

' .Iutreating a plate l9 itisfacewise compressedbetweenthe-surfaces 8iwith a treat; ment sheet 15, containing the pattern of the material 17, interposed-between the-back of the plate and the respective surface 8 and I with the pattern of material in ,Plastic con; dition, by forcing the upper pressure 11 893- her 3 downwardly byine'ansof theScrewe turned by :the hand wheel'- v5.- .Under -J-the pressure the material.17,}displaces to. coin form the face of the plate-*w-itlnthe respective sur-face8',the material;: 17,disphQing-in v r the respective surface 8,-the pattern provid 'ing displacement space throughout the area a varied manner, in correspondence with any varying thickness of the plate where the com pression is effected between corresponding unyielding or fiat unyielding surfaces, to exert sufficient pressure throughout the areaof the plate to conform the face thereof with of the material to avoid concentrating the pressure on any portion of the plate whereby the face of such portion of the plate might be injured by undue pressure thereon. Figs. 3 and i show the plate before treatment with a portion 21 of theface of the plate depressed and a portion 22 of the face of the plate projecting, the port-ion 22 overlying an unduly thick portion of the plate as shown in Fig. i. Fig. 5 shows this portion of the plate after treatment with the depression and projection removed, and the pattern of material 17 of the treatment sheet displaced whereby the face of the plate was conformed with the respective surface 8 without concentrating pressure onthe unduly thick por tion of the plate underlying the portion 22 of the face thereof. I

It'is preferable to apply heat to the plate to render the plate more pliable during the compression and where heat is so used it is desirable to use a. pattern of material 17 which is normally hard and unyielding and adapted to be rendered plastic under the heat whereby the heat is utilized for both purposes, the use of heat to soften the pattern of material having an advantage in that the material can be rendered uniformly plasticwithout particular skill or care being required. I g i The preferred manner of applying the 7 heat to the plate and material is by heating the surfaces 8 which in the machine shown is effected by the gas burners 12. The degree of heat used for the above purposes is approximately 350 F. though it may be varied throughout a fairly large range.

lVhere heat is used to render the plate more pliable it is preferable to cool the plate, after it is treated to conform the face thereof, while held under compression in its conformed state whereby to prevent warping the same. This is efiected bycooling the plate and the treatment sheet while they are unyieldingly held, with the treatment sheet applied on the back of the plate and in registered posit-ion with respect to the face of the plate, in their respective conformed and displaced states, for example, by per mitting the surfaces 8 to cool with the plate and treatment sheet still under compression.

therebetween or by placing the plate and treatment sheet under compression in another press having fiat unyielding compression' surfaces which are cool.

After the plate is treated the back of the same is either shaved to level the same or the treatment sheet, if it is adapted tobe or become hardened, is left, in its displaced form'andin hardened condition and 111 registry with the face of the plate, on the back of the plate, and preferably secured thereto, to form an even solid back or seat for the plate. I

In the manufacture of duplicate plates from original plates or foundry forms the from the corrected face of the original whereby the duplicate. is practically free "from defects ori inally obtaining in the original, so'that the correction of the duplicate, if any, is only to correct remainders of defects practically eliminated in the treatment of the original and such defects as obtained in the duplicate in the making of the same from the corrected face of the original. The duplicate plate so formed'is thereafter preferably treated to conform the, face thereof with the aforementioned desired surface. The original plate or foundry form-is preferably treated in the same manner hereinbefore described by facewise compressing the same between unyielding surfaces with a pattern of material in plastic condition, capable of being" or becoming hardened, in

terposed between the back of the plate and rial as is-usual, but with the pattern of material in its displaced form and in hardened condition-applied to the back of this plate and in registered position with the face thereof and with an unyielding surface supporting the pattern of material for maintaining the conformed face of this plate during the molding. Thereafter a duplicate plate is produced from the original, as by the usual electrotype method. Thereafter the duplicate plate may be again treated, if necessary, in the same manner as hereinbefore described; The original and duplicate plates may be treated in the machine illustrated in Fig. 1 as is obvious, and the back of the duplicate plate. may be shaved after the treatment thereof to level the same in the usual manner. 7 n

This method of manufacturing vduplicate plates from originalplates or foundry forms produces a duplicate plate of a high degree kindsofpla-tes:or forms, Further in the use of; the term original plate; orvfoundry form I mean any plate or form used as an original from which duplicate, plates are made-. V

WVhile I have herein described and shown one'embodimentof my; invention I do not wish to be limited to the precise details thereof as changes may readily be made without departing from the spirit of my invention but having thus described my invention I claim as new and desire to secure by Letters Patent the following:

1. The process of treating a printing plate consisting in facewise compressing the plate between unyielding surfaces with a pattern of suitable material in plastic condition interposed between the back of the plate and the respective unyielding surface,

said pattern affording displacement space throughout the area of said material and said material being adapted to displace under the pressure to conform the face of the plate with the respective unyielding sur-' J! race. 7

2, The process of treating a printing plate consisting 1n facewise compressing the plate between corresponding; true, and unyielding surfaces with a pattern of suitable material of uniform-thickness and in plastic condition interposed between the back of the plate and the respective unyielding surface, said pattern providing uniform displacement space throughout the area of said material and said material being adapted to displace under the pressure to con form the face of the plate with the respective unyielding surface.

3. The process of treating a printing plate consisting in facewise compressing the plate between unyielding surfaces with a pattern of suitable material in plastic condition interposed between the back of the plate and the respective unyielding surface, said pattern providing displacement space throughoutthe area of the material and said material being adapted to displace un-' der the pressure to conform the face of the plate with the respective unyielding surface, and then shaving the back of the plate 7 to level the same. 1

4. The process of treating a printing plate consistlng 1n facewlse compressing the plate between unyieldingsurfaces with a pattern of material, normally hard and unyielding and adapted to become plastic when heated, interposed between the back of the plate and the respective unyielding surface and applying heat to both the plate and the pattern of material to render the plate more pliable and to render the material plastic during the compression, saidpattern providing displacement space through- .out the area of the material and said material being adapted under the heat to displace u-nder theiv pressureteconform the face of -the plate.

5. The process of treating a printing plate consisting in facewise compress ng the a plate between corresponding, true, and unyielding surfaces, heated to a point to render the plate more pliable, with a pattern of material of uniform thickness, normally plate while heated to render it more pliable between-unyielding surfaces with a pattern of materialin plastic condition interposed between the back of the plate and the respective unyielding surface, said pattern providing displacement space throughout the area 'of the material and said material being adapted to displace to conform the face of the plate with the respective surface, and then cooling the plate while held under compression in its conformed state.

7 The process of treating a printing plate consisting in facewise compressing the plate between corresponding unyielding surfaces with pattern of material, normally hard and unyielding and adapted to become plastic when heated and to become hardened when cooled, interposed between the back of the plate and the respective unyielding surface andapplying heat to both the plate and the material .to render the plate more pliable and to render the material plastic during the compression, said pattern providing displacement space throughout the area of the material and said material being adapted under the heat to displace under the pressure to conform the face of the plate with the respective unyielding surface, and then cooling the plate and material while the plate and material are unyieldingly held, in the aforementioned relation" and in registered position, under compression in their respective conformed and displaced states,

8. The process of treating a printing' plate consisting in facewise compressing the plate between flat unyielding surfaces, heat ed to a point to render the plate more pliable, with a pattern of material ofuniform thickness, normally hard and unyieldin and adapted to become plastic when heated and to become hardened when cooled, in-

terposed between the back of the plate and the respective unyieldingsurface, said pat-- tern providing uniform displacement space throughout the area of the material and said material being adapted under the heat to displace under the pressure to conform the face of the plate with the respective unyielding surface; and then cooling the plate and n'mterial by subjecting them in the aforementioned relation and 111 registered position to pressure between cool flat unyielding surfaces to hold them unyielclingly in their respective conformed and displaced states while ceeling.

In Witness whereof I hereunto afiix my signature this eighteenth clay ofDecember, 7

SAMUEL E. DETTMAN. 

